avcodec/qsvenc: Fix leak of A53 data

Up until now, it has only been freed when the QSVFrame is reused,
so that the last one contained in it leaked at the end.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/qsvenc.c

@@ -1612,6 +1612,7 @@ int ff_qsv_enc_close(AVCodecContext *avctx, QSVEncContext *q)
     while (cur) {
         q->work_frames = cur->next;
         av_frame_free(&cur->frame);
+        free_encoder_ctrl_payloads(&cur->enc_ctrl);
         av_freep(&cur);
         cur = q->work_frames;
     }